<template>
  <div class="todo-footer" v-show="total">
    <label>
        <!-- <input type="checkbox" :checked="isAll" @change="checkAll"/> -->
        <input type="checkbox" v-model="isAll"/>
    </label>
    <span>
        <span>已完成{{doneTotal}}</span> /全部{{total}}
    </span>
    <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
</div>
</template>

<script>
export default {
    name:'MyFooter',
    props:['todos'],
    computed:{
        total(){
            return this.todos.length
        },
        doneTotal(){
            // reduce最后的返回值是最后一次调用函数的返回值
            // const x = this.todos.reduce((pre,current)=>{
            //     return pre + (current.done ? 1:0)
            // },0)
            return this.todos.reduce((pre,todo)=>{
                return pre + (todo.done?1:0)
            },0)
        },
        // isAll(){
        //     return this.doneTotal === this.total && this.total > 0
            
        // }
        isAll:{
            get(){
                return this.doneTotal === this.total && this.total > 0
            },
            set(value){
                // this.checkAllTodo(value)
                this.$emit('checkAllTodo',value)
            }
        }
    },
    methods:{
        checkAll(e){
            this.checkAllTodo(e.target.checked)
        },
        clearAll(){
            // this.clearAllTodo
            this.$emit('clearAllTodo')
        }
    }
    
}
</script>

<style scoped>
    .todo-footer{
        height: 40px;
        line-height: 40px;
        padding-left: 6px;
        margin-top: 5px;
    }

    .todo-footer label{
        display: inline-block;
        margin-right: 20px;
        cursor: pointer;
    }
    .todo-footer label input{
        position: relative;
        top: -1px;
        vertical-align: middle;
        margin-right: 5px;
    }
    .todo-footer button{
        float:right;
        margin-top: 5px;
    }
</style>
